DE102014007623A1 - Device for storing gas - Google Patents

Abstract

The invention relates to a device (1) for storing gas under high pressure, with an inner shell and an outer shell (2) surrounding the inner shell, with a measuring device for detecting damage to the outer shell (2). The device according to the invention is characterized in that the measuring device is designed in the form of at least one electrically conductive wire (4) extending over almost the entire surface of the outer casing (2).

Description

The invention relates to a device for storing gas under high pressure according to the closer defined in the preamble of claim 1.

For storage of gas, containers in which the gas is stored under high pressure are known from the general state of the art. For example, for compressed natural gas or for hydrogen, which are used at nominal pressures of 260 bar or 700 bar, for example in vehicles, so-called type-III or type-IV compressed gas storage are well known and common. These consist of an inner shell, the so-called liner, which is formed for example of a metallic material or plastic. The primary purpose of this inner shell is to ensure tightness against the gas stored in the device. The inner sheath is then surrounded by an outer sheath, typically a fiber composite material, which alone would not be tight for the stored gas, but which is sufficiently stable to withstand even high pressures easily. This combination of inner shell and outer shell then forms the device for storing gas, which is also referred to as compressed gas storage.

Since the outer shell is relevant to the pressure resistance of the device, potential damage to the outer shell, particularly when used in vehicles, would pose a significant safety problem. Therefore typically a surface inspection of the device by a technical expert must be done every 48 months.

From the prior art in the form of DE 101 54 145 C1 a device for the continuous monitoring of Kompositdruckgasbehältern is known. This device is based essentially on a strain gauge, which is evaluated for example via a bridge circuit. This makes it possible to detect an expansion of the gas cylinder. Exceeds the expansion, for example, during refueling, the permissible for the respective container type elongation, then it must be assumed that an error, which can be displayed accordingly, for example via an alarm via a control unit or the like.

The disadvantage of the structure described therein is that only the entire container can be monitored as such. Thus, partially occurring damage in the outer shell can only be detected when the entire container is affected by such a weakening of the outer shell. This is a disadvantage.

From the further general state of the art it is from the US 4,107,672 A for use in containers for storing very cold liquids, for example liquid gases or the like, it is known that the heat-insulating layer of the container can be monitored by means of sensitive, fragile, electrically conductive elements with regard to damage to the heat-insulating layer. If there is damage to the heat-insulating layer, then the sensitive electrical elements are damaged and a complex evaluation or a correspondingly complex mechanical system, as described in the document, such damage and its position can be determined. The structure has the disadvantage that it is irreversible and very sensitive, which is highly undesirable in particular for the use of a device for storing gases under high pressure, which is to be used in vehicles, since vibrations could already trigger an unjustified alarm. Also, contraction and expansion of the container, which is inevitable in the storage of gases under high pressure, such as when the container is refueled or illuminated by the sun, would lead to an undesirable alarm, so that the structure for use in pressurized gas containers is completely unsuitable.

The object of the present invention is now to provide an improved device for storing gas under high pressure according to the first-mentioned prior art.

According to the invention this object is achieved by a device having the features in claim 1. Advantageous embodiments and further developments emerge from the subclaims dependent thereon. In claim 5, a particularly preferred use is also indicated.

In the inventive device for storing gas under high pressure, for example, for storing compressed natural gas at a nominal pressure of 260 bar or hydrogen at a nominal pressure of 700 bar, it is provided that comparable as in the first-mentioned prior art in the outer shell a Measuring device is provided for detecting damage to the outer shell. Unlike in the prior art, this measuring device according to the invention in the form of at least one electrically conductive over the approximately entire surface of the outer shell extending wire is formed around or in the outer shell. Such a wire can be very simple in terms of its electrical conductivity or its electrical resistance are monitored. It is nevertheless relatively stable and elastic so far that it easily participates in the movements occurring in such a compressed gas container, for example a pressure-dependent expansion and contraction of the compressed gas container. If the outer shell is damaged somewhere, then it is in this area, the wire, so that the conductivity is no longer given or limited. Accordingly, an error can be closed and an alarm triggered. Unlike in the prior art, no limit values need to be specifically monitored for this, but in particular, it is only possible to check for electrical continuity of the wire.

According to a very advantageous development of the idea, the wire can be designed as a net, as at least one meander or as at least one spiral. This makes it possible to easily and efficiently monitor the entire surface of the outer shell with one or a few wires and correspondingly few electrical connections.

In particular, the design as a spiral or meander, preferably in the form of at least two crossing electrically non-interconnected at the crossings meanders or spirals, is very simple in terms of evaluation, because only the two meanders or spirals must be monitored for electrical continuity. If the conductivity no longer exists due to an interruption, then a corresponding alarm can be triggered via a control unit.

The structure of the device is extremely simple and efficient and very safe and less prone to mechanical disturbances such as vibrations or the like. It is therefore particularly suitable to be used in environments which are exposed in operation corresponding shocks, vibrations and higher temperature fluctuations, and which nevertheless have a high security risk, so that the best possible monitoring of the device is necessary. Such applications can be found in particular in vehicles in which the gas stored in the device can be used for example for driving an internal combustion engine or a fuel cell. The preferred use of the device is therefore its use for storing fuel in vehicles.

Further advantageous embodiments will become apparent from the embodiments, which are described below with reference to the figures.

Showing:

1 a compressed gas storage according to the invention in a first possible embodiment;

2 a compressed gas storage according to the invention in a second possible embodiment; and

3 a compressed gas storage according to the invention in a third possible embodiment.

In the presentation of the 1 is a device in principle 1 for storing gases under high pressure, for example for storing compressed natural gas or hydrogen as fuel for a vehicle. The device 1 , which also like compressed gas storage 1 is designated, it is from an unrecognizable inner shell with a surrounding outer shell 2 be realized. The outer shell 2 should preferably be made of a fiber-reinforced plastic material, so that it is in the device 1 is a so-called type-III or type-IV compressed gas storage.

As in such compressed gas storage, the outer shells for the pressure resistance and mechanical strength of the compressed gas storage 1 highly relevant, they provide a safety-critical part of the device 1 which must be checked accordingly frequently. In order to achieve a continuous inspection of the outer shell so that surveys by technical experts can be dispensed with, and that a continuous monitoring of the outer shell 2 Damage is possible in the presentation of the 1 a wire mesh in the form of a net in the outer shell 2 integrated or attached to its surface. Such a network of a wire 4 , which below also as alarm wire 4 is called, allows continuous monitoring of the outer shell 2 , as damage to the outer shell practically always with damage to the alarm wire 4 would go along. About a preferably in the range of a valve 3 the device 1 attached control unit 5 may be monitoring, preferably electrical monitoring, of the alarm wire 4 take place, in particular in the way that the alarm wire 4 on conductivity and thus on a possible breakage of the wire 4 is monitored. If one occurs, an alarm can be triggered so that it can respond before a safety-critical situation arises.

In the representations of the 2 and 3 Two alternative embodiments of this idea are shown. Instead of a network from the alarm wire 4 is in the representation of 2 a spiral wrapping of the outer shell 2 with the alarm wire 4 shown. Only a single wire is used, so that it can be evaluated very easily with regard to its electrical continuity. The wire breaks at any point as a result of damage to the outer shell 2 , this is no longer electrically continuous. To the outer shell 2 cover as completely as possible, the spiral can be correspondingly tight. An alternative to this would be the spiraling back around the individual sections of the alarm wire 4 to position them closer together, or as shown in the illustration of the 3 It can be seen, the wrapping with two opposing spirals, either once on the way and once on the way back, or completely independently. Other alternatives would be, for example, a meandering arrangement of the alarm wire 4 , which would then realize in the use of two different alarm wires, which are not electrically connected at the crossing points, approximately the area coverage of the net-like structure. Unlike a network, which is relatively difficult to evaluate in terms of breakage of the wire in one of the meshes, then an evaluation of the two wires could be done independently or in a series connection also together, so very easily and efficiently via the control unit 5 a possible breakage of the wire 4 as a result of damage to the outer shell 2 to be able to recognize. The control unit 5 Accordingly, it could trigger an alarm to prevent safety-critical situations.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10154145 C1 [0004]
• US 4107672 A [0006]

Claims (5)

Contraption ( 1 ) for storing gas under high pressure, with an inner shell and an outer shell surrounding the inner shell ( 2 ), with a measuring device for detecting damage to the outer shell ( 2 ), characterized in that the measuring device in the form of at least one electrically conductive over the approximately entire surface of the outer shell ( 2 ) extending wire ( 4 ) is trained. Contraption ( 1 ) according to claim 1, characterized in that the wire ( 4 ) in the form of a network or at least one meander or at least one spiral is formed. Device according to claim 1 or 2, characterized in that the wire ( 4 ) with an electrical control unit ( 5 ), which is arranged so that the integrity of all sections of the wire ( 4 ) is testable. Contraption ( 1 ) according to claim 1, 2 or 3, characterized in that a control device ( 5 ) is provided, which with the wire ( 4 ), and which is adapted, in the event of damage to the wire ( 4 ) to trigger an alarm. Use of a device ( 1 ) according to one of claims 1 to 4, for storing hydrogen or compressed natural gas as fuel for a vehicle.

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